2.4 LAMP and conventional PCR
WarmStart® LAMP Kit (New England Biolabs, Ipswich, MA) used for LAMP
assay. General protocol of LAMP was flowed by manufacture’s guideline in
a 25 μl reaction mixture. For the conventional PCR, TOYOBO KOD‐FX
TaqTM (Toyobo Life Science, Osaka, Japan) used in this
study. Species-specific primers with the following PCR amplification
protocol: a 2‐min denaturing step at 94°C and a PCR amplification cycle
consisting of denaturing at 94°C for 20 s, annealing at 60°C for 20 s,
and extension at 68°C for 30 s, which was repeated 35 times. The
amplified DNA fragments were separated using 1.5% agarose gel
electrophoresis, visualized with SYBR green (Life Technologies, Grand
Island, NY). Used insect samples were collected in Korean cornfields
except S. littoralis . MPI-CE lab strain of S. littoralisand mitochondrial genome sequenced S. frugiperda samples (Jeju,
Muan and Miryang) used. Pheromone traps were used as previously reported
to collect samples (S. exigua, S. litura, Mythimna separate, andHelicoverpa armigera ). Traps were set in Pyeongchang (37°40.53 N,
128°43.49 E), Hongchen (37°43.35 N, 128°24.33 E) and Gangneung (37°36.56
N, 128°45.59 E)(J. Kim, Kwon, Park, & Maharjanm, 2018). DNA samples
were prepared using DNAzol from trapped adults. Two or three biological
DNA samples were used in each LAMP and PCR.
RESULTS